Oops, forgot to attach the NcML file...still on my first cup of coffee! Sean > Greetings Larry! > > I've taken a look at your file, and you are correct that the issue is that it > is not > CF compliant. I've attached an NcML file to this email, and if you place this > in > the same directory as your netCDF file and load it (the NcML file) into the > IDV, > things will work as you expect. > > This fix will allow you to use the IDV with your model out. Please keep in > mind > that this will not make it CF compliant, but rather "good enough" for the IDV. > > The main issue: > > The time variable, t, has a unit attribute set to hours and a attribute > ReferenceTime > set to the reference time - in order to be CF compliant, the reference time > must > be part of the unit: > > attribute unit : "hours since 1991-03-19 18:00:00" > (see > http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#time-coordinate) > > All this NcML file does is change the attribute unit on the time variable t. > Note that > if you want to use this on a different file, you will need to edit the second > line of the > NcML file to correctly reference the new netCDF file. To make life easier, > you may > want to contact the modeling group and see if they would fix the unit for t > in their > code. > > Also, I would strongly recommend that when working with this data, you use the > "Predefined -> South America" projection and turn off the option "Auto-set > Projection" - both are found under the Projections menu just above the main > view window. If you don't do this, you will get some pretty funky artifacts > due > to the prime meridian. > > Cheers! > > Sean > > > Dear support-idv: > > > > I am unable to import a time-varying 2-d gridded netcdf variable into idv > > and was wondering if you might have some advice as to what I'm doing wrong. > > > > For example, I am using the following netcdf file: > > ftp://ftpext.usgs.gov/pub/wr/wa/vancouver/Mastin/Ash3d/3d_tephra_fall.nc > > > > I am attempting to read the 2-D, time-dependent variable cloud_load, whose > > properties are given as follows when I type "ncdump -h" > > > > double cloud_load(t, lat, lon) ; > > cloud_load:long_name = "Cloud Load" ; > > cloud_load:units = "T/km2" ; > > cloud_load:missing_value = "-9999.f" ; > > cloud_load:_FillValue = -9999. ; > > > > When I open this file using the IDV data chooser, only three variables are > > visible, as you can see in the attached screenshot: > > > > Deposit arrival time > > Airborne ash arrival time > > Cell area > > > > These variables are 2-D gridded, non-time dependent variables, having the > > dimensions: > > > > double depotime(lat, lon) ; > > double ash_arrival_time(lat, lon) ; > > double area(lat, lon) ; > > > > The netcdf file contains several other variables with dimensions (t, lat, > > lon), like cloud_load, but none of these show up. > > > > Our modeling group wrote the code that creates the netcdf file and we think > > the file is nf-compliant. > > > > Do you think this is an issue involving compliance with netcdf conventions, > > or is there a trick to viewing time-dependent gridded netcdf data that I > > haven't yet found? > > > > Your help would be appreciated. > > > > Thanks, > > > > Larry Mastin > > > > > > -- > > U.S. Geological Survey > > David A. Johnston Cascades Volcano Observatory > > 1300 SE Cardinal Court, Bldg. 10, Suite 100 > > Vancouver, WA 98683 USA > > tel. (360) 993-8925 > > fax (360) 993-8980 > > > > Ticket Details =================== Ticket ID: ALX-750694 Department: Support IDV Priority: Normal Status: Open
Attachment:
3d_tephra_fall.ncml
Description: Binary data